Experiment #4: Effect of Temperature on Chemical Kinetics Objective: The purpose of this experiment is to determine the activation energy of the reactions between KMnO4 and H2C2O4 under different temperatures by using the Arrhenius Equation. Procedure: 1. Create 3 water baths, each at varying temperatures (approximately 10℃, 20℃, and 30℃) and an ice bath for about 0℃ making sure that the difference in temperature of each bath is roughly 10℃ apart. 2. Use a buret to place 20mL of 0.5M H2C2O4 in an Erlenmeyer Flask and 10mL of 0.02M KMnO4 in a 15cm test tube. 3. For the 0℃, put Erlenmeyer Flask into another flask of ice to maintain the temperature. For the others, put the flask into the water baths. 4. Mix the reactants and record the time it takes for the solution to turn yellow/brown. Swirl the contents regularly as you wait for the reaction to occur. 5. Repeat the procedure for your second trial at the temperatures again beside to 0℃. 6. Find the average time of the trials and then determine k for each temperature. 7. When complete, determine the Activation Energy from the slope after plotting ln(k) v 1/T. Data Collection: KMnO4 (mL) H2C2O4 (mL) Temp. (0C) Reaction Time (Trial 1) (s) Reaction Time (Trial 2) (s) Average Time (s) 10 20 0 1312 NA 1312 10 20 10 642 604 623 10 20 20 368 390 379 10 20 30 124 116 120 Calculations: ● Determining rate:Temp. (0C) Rate Calculation (Rate =[KMnO4]/t) 0 0.02/1312=1.52E-5 10 0.02/623=3.21E-5 20 0.02/379=5.28E-5 30 0.02/120=1.67E-4 ● Determining k: Temp. (0C) k Calculation (k = Rate/([KMnO4][H2C2O4])) 0 1.52E-5/(0.02*0.5) = .00152 10 3.21E-5/(0.02*0.5) = .00321 20 5.28E-5/(0.02*0.5) =.00528 30 1.67E-4/(0.02*0.5) = .0167 ● Determining EA: Temp. (C) Temp. (K) 1/T (1/K) k (Rate) Ln(k) Slope (From graph) EA (J/mol) 0 273 .003663 .00152 -6.489 -9576.92 1151.9 10 283 .003533 .00321 -5.741 -9576.92 1151.9 20 293 .003412 .00528 -5.244 -4107.44 494.04 30 303 .0033 .0167 -4.092 -10285.7 1237.15 Ea= -(slope)/R R= 8.314 J/molDiscussion: Bond energy is the amount of energy required to break a certain chemical bond; activation energy is the amount of energy needed for a reaction to occur. Therefore, if bond energy is high, it will require a higher activation energy in order for the reaction to happen. In our experiment, from the data, we can see a trend that as temperature increased, activation energy seems to decrease with an exception towards the end that could have been caused by a data collection error. Result: The purpose of this experiment is to determine the activation energy of the reactions between KMnO4 and H2C2O4 under different temperatures by using the Arrhenius Equation. From this we can see there is a negative correlation between temperature increase and activation